:root {
    --color1: #ff0000;
    --color2: #0000ff;
    --color3: #00ff00;
    --color4: #ff00ff;
    --glow-color: #ffffff;
    --beat-interval: 0.5s; /* Default: 120 BPM */
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    font-family: 'Inter', sans-serif;
    background: radial-gradient(circle at center, var(--color1) 0%, var(--color2) 30%, var(--color3) 60%, var(--color4) 100%);
    background-size: 200% 200%;
    animation: gradient 12s ease infinite;
    overflow: auto;
    position: relative;
}

body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    opacity: 0.5;
    animation: particle var(--beat-interval) ease-in-out infinite;
    pointer-events: none;
}

.container {
    max-width: 720px;
    width: 90%;
    text-align: center;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.visualizer {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
}

#record {
    width: 350px;
    height: 350px;
    margin: 0 auto 20px;
    background: radial-gradient(circle, #222 10%, #000 11%, #000 100%);
    border-radius: 50%;
    position: relative;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.6);
    overflow: hidden;
    border: 2px solid transparent;
}

#record::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: repeating-radial-gradient(circle at center, transparent, transparent 2.5px, rgba(255, 255, 255, 0.1) 2.5px, rgba(255, 255, 255, 0.1) 5px);
    border-radius: 50%;
}

#record::after {
    content: '';
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    bottom: 10px;
    background: linear-gradient(45deg, rgba(255, 255, 255, 0.3) 0%, transparent 50%, rgba(255, 255, 255, 0.3) 100%);
    border-radius: 50%;
    animation: highlight 3s linear infinite;
}

#label {
    width: 120px;
    height: 120px;
    background-size: cover;
    background-position: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    border-radius: 50%;
    border: 3px solid #fff;
    box-shadow: 0 0 12px rgba(0, 0, 0, 0.4);
}

.spin {
    animation: spin 3s linear infinite, wobble 2s ease-in-out infinite, border-pulse var(--beat-interval) ease-in-out infinite;
    box-shadow: 0 0 8px var(--glow-color), 0 10px 20px rgba(0, 0, 0, 0.6);
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@keyframes wobble {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(0.98); }
}

@keyframes highlight {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@keyframes border-pulse {
    0%, 100% { border-color: transparent; }
    50% { border-color: var(--glow-color); }
}

@keyframes gradient {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

@keyframes particle {
    0%, 100% { transform: translateY(0); opacity: 0.5; }
    50% { transform: translateY(-10px); opacity: 0.7; }
}

.pulse.bass-scale {
    animation: pulse var(--beat-interval) ease-in-out infinite alternate, bass-scale var(--beat-interval) ease-in-out infinite;
}

@keyframes pulse {
    from { opacity: 0.7; }
    to { opacity: 1; }
}

@keyframes bass-scale {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.02); }
}

.spacer {
    height: 100px;
}

.controls {
    position: absolute;
    bottom: 20px;
    width: 100%;
    text-align: center;
}

button {
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 700;
    color: #fff;
    background: #333;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}

button:hover {
    background: #555;
    transform: scale(1.05);
}

.song-info h2 {
    font-size: 24px;
    color: #fff;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
    margin-bottom: 10px;
}

.song-info p {
    font-size: 18px;
    color: #ddd;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.upload-form {
    background: rgba(255, 255, 255, 0.1);
    padding: 30px;
    border-radius: 10px;
    backdrop-filter: blur(10px);
    max-width: 500px;
    width: 100%;
}

.upload-form h1 {
    font-size: 28px;
    color: #fff;
    margin-bottom: 20px;
}

.upload-form label {
    display: block;
    font-size: 16px;
    color: #fff;
    margin: 10px 0 5px;
}

.upload-form input[type="file"],
.upload-form input[type="text"],
.upload-form input[type="number"],
.upload-form input[type="checkbox"] {
    width: 100%;
    padding: 10px;
    font-size: 14px;
    border: 1px solid #ccc;
    border-radius: 5px;
    margin-bottom: 15px;
}

.upload-form input[type="checkbox"] {
    width: auto;
}

.upload-form button {
    width: 100%;
    background: #6200ea;
}

.upload-form button:hover {
    background: #7f39fb;
}

.error {
    color: #ff4444;
    margin-bottom: 15px;
}

@media (max-width: 600px) {
    #record {
        width: 250px;
        height: 250px;
    }
    #label {
        width: 80px;
        height: 80px;
    }
    .song-info h2 {
        font-size: 20px;
    }
    .song-info p {
        font-size: 16px;
    }
    .container {
        max-width: 360px;
    }
}